Bullet shells litter the ground at Tripoli International Airport after fierce fighting in August (Picture: AFP/Getty)

US officials say 11 commercial aircraft have gone missing from Tripoli International Airport in Libya – ahead of the 13th anniversary of the September 11 attacks on New York and Washington.

The airport was the scene of a fierce battle that ended on August 26, when fighters from the Islamic Fajr Libya (Dawn of Libya) coalition captured the airport and aircraft belonging to the state-owned Libyan Airlines and Afriqiyah Airways.

Pictures from the airport in the aftermath of the fighting showed severely damaged and totally destroyed aircraft.

Dawn of Libya was identified as a terrorist organisation by the Libyan government earlier this year.

While the US State Department is down-playing the significance of the missing planes, one official was quoted in the Washington Free Beacon as saying: ‘There are a number of commercial airliners in Libya that are missing. We found out on September 11 what can happen with hijacked planes.’

September 11 also marks the second anniversary of the raid of the US Ambassador’s compound in Benghazi, Libya, where four Americans – including including US Ambassador Christopher Stevens – were killed.

Intelligence reports of the stolen aircraft include a warning that one or more of the planes could be used in terrorist attacks in the region. Another scenario involved using a plane with civilian markings to transport armed terrorists to an airport usually open to commercial aircraft.

Al Jazeera reported that the planes are being held by a group called the Masked Men Brigade, and it plans to use them in terror attacks.

Tunisia and Egypt have stopped flights to and from Libya, and countries including Algeria, Morocco and Nigeria are on high alert.

Egypt has conducted limited airstrikes in Libya and is considering increased military action, including ground forces.